Coal-drill.



PATENTED OCT. 17, 1905.

C. W. GOWELL.

GOAL DRILL.

APPLICATION TILED JULY 11, 1904.

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GOAL DRILL.

APPLICATION FILED JULY 11. 1904.

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UNITED STATES PATFT FFIOE.

CHARLES W. GOWELL, OF NOVINGER, MISSOURI, ASSIGNOR OF ONE-HALF TO JAMES C. SEFTON, OF TROY, ILLINOIS.

COAL-DRILL.

Specification of Letters Patent.

Patented Oct. 17, 1905.

Application filed July 11, 1904. Serial No. 216,018.

To all whom it may concern:

Be it known that I, CHARLES W. CoWELL, a citizen of the United States, residing at Novinger, Adair county, State of Missouri, have invented certain new and useful Improvements in Goal-Drills, of which the following is a specification containing a full, clear, and exact description, reference being had to the accompanying drawings, forming a part hereof.

My invention relates to coal-drills; and it consists of the novel features herein shown, described, and claimed.

In the drawings, Figure 1 is a perspective of a coal-drill embodying the principles of my invention. Fig. 2 is an enlarged detail illustrating the construction of the drilling mechanism. Fig. 3 is a view showing the coal in section and illustrating the operation of the drill. Fig. 4 is across-section on the line 4 4 of Fig. 3. Fig. 5 is an end elevation showing the chucks for holding the bits. Fig. 6 is a side elevation showing the bits in the chucks. Fig. 7 is a front elevation of the longest and narrowest bit. Fig. 8 is a front elevation of the intermediate bit. Fig. 9 is a front elevation of the shortest and widest bit. Fig. 10 is a cross-section of the feed-screw on the line 10 10 of Fig. 2.

Referring to the drawings in detail, the feed-crew 11 has two oppositely-arranged keyseats 12 and 13, as shown in Fig. 10. The feed-screw 11 is mounted and operated in the The drillshank 14 has a straight opening or bore 15 extending from one end to the other, and the head 16 of the drill-shank is enlarged and has a tapered opening 17, connecting with the opening 15 to receive the point of the feedscrew 11,said point being squared, and the opening 17 being correspondingly squared to prevent rotation of the feed-screw relative to the drill-shank, and a spring-cotter 18 is inserted through the head 16 and through the point 19 of the feed-screw tohold the feedscrew and drill-shank removably together.

The coal conveyer threads 20 21 22 extend from the point'of the drill-shank 14 to the head 16, said threads being arranged parallel and spiral. The bit holders 23 24 25 are formed on the back sides of the coal-conveyer threads 20 21 22 and have sockets 26 to receive the shanks of the bits and set-screws 27 to hold the shanks in position. The bits 28 29 30 each have a shank 31 to be inserted into the sockets 26 and are engaged by the set-screws 27. The bit 28 is, say, three-eighths of an inch wide and five-eighths of an inch long. The bit 29 is shorter and wider than the bit 28, and the bit 30 is shorter and wider than the bit 29, so that when the bits are arranged in rotation, as shown in Fig.6, the bit 28 will cut a narrow groove 32, the bit 29 will follow the bit 28 and widen the groove, as indicated by 33, and the bit 30 will follow the bit 29 and finish the groove, as indicated by 34, the finished part 34 being wide enough to receive the drill-shank 14 and the coal-conveyer threads 20 21 22, as shown in Figs. 3 and 4, thus leaving a core 35 of coal in the bore 15.- In an ordinary coal-drill forming a hole two and one-half to three inches in diameter the bit 30 should be from one-half to five-eighths of an inch in width, so that the finished groove 34 will make a core 35 somewhat smaller than the bore 15 and will make an opening 36 somewhat larger than the diameter of the threads 20 21 22, so that the drill will slide readily backward or forwardlyin said opening. The core 35 will break loose from the coal bank at frequent intervals and will be drawn out with the drill. The front face 37 of each bit is in alinement with the front face 38 of each coalconveyer thread, so that the coal cut loose by the bits will slide readily along said front faces 38 and be carried outwardly by the coalconveyer threads as the drill is rotated. By arranging a set of graduated bits in rotation I provide means whereby the bits will cut freely and not choke, as would be the case if the bits were all alike or if only a single bit was used. By using two key-seats 12 and 13 upon the feed-screw 11 I balance the friction between the feed -screw and the feed-nut, thereby avoiding the tendency to stick and the tendency to bend the feed-screw.

The drill shank 14 with the conveyerthreads may be cast or formed in any suitable way, and by attaching the bits directly to the drill-shank Without the interposition of the chuck I greatly simplify and cheapen the construction.

One of the great advantages of my coaldrill is the fact that the core 35 may be broken loose from the coal bank and removed in chunks instead of being cut up and pulverized, thus greatly reducing the amount of cutting to be done by the bits.

It is important that the threads upon the said sockets; and set-screws screw-seated in bit-holders to hold the bits in place.

2. In a coal-drill: a hollow drill-shank 14;

the coal-conveyer threads 20 21 22 upon drillshank; of bit-holders 23 24 25 at the back sides of the coal-conveyer threads, and having sockets to receive the shanks of the bits; bits 28 29 30 mounted in the bit-holders, said bits being graduated in length and width; the widest bit being the shortest, and the narrowest bit being the longest.

In testimony whereof I have signed my name to this specification in presence of two subscribing witnesses.

OHARLES W. COW ELL.

Witnesses:

CHAs. POLK, ED BENSON. 

